Question 1

What fall do 50 mm rise firrings give over a 2.4 m length?

Accepted Answer

A 50 mm rise over 2.4 m gives a fall of approximately 1:48, which exceeds the 1:60 minimum recommended under Building Regulations Part C for flat roofs. This makes the 2.4 m length suitable for short roof spans where a steeper fall is acceptable.

Question 2

Can I order firrings cut to a specific length?

Accepted Answer

Yes. Nottage Timber Merchants cuts firrings to your specification. The standard lengths available online are 1.2 m, 2.4 m, 3.6 m and 4.8 m. For bespoke lengths or quantities, call the yard on 01656 745959 with your measurements and the team will advise on the most suitable option.

Question 3

What timber grade are your firrings cut from?

Accepted Answer

Firrings are cut from C16 or C24 graded structural softwood, the same grades used for joists and rafters on UK construction projects. Both grades are suitable for flat roof applications, though C24 offers a higher strength classification where structural loading requires it.

Property	Detail
Material	Structural softwood
Grade	C16/C24 sawn
Finish	Sawn
Profile	Tapered (firrings)
Rise	50 mm
Available lengths	1.2 m, 2.4 m, 3.6 m, 4.8 m
Cut	Cut to order

Specifications

What it's used for

Fitting and handling

FAQ

Sawn Timber Firrings Cut to Order